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| - | [[Image:1eue.gif|left|200px]] | + | {{Seed}} |
| | + | [[Image:1eue.png|left|200px]] |
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| | {{STRUCTURE_1eue| PDB=1eue | SCENE= }} | | {{STRUCTURE_1eue| PDB=1eue | SCENE= }} |
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| - | '''RAT OUTER MITOCHONDRIAL MEMBRANE CYTOCHROME B5'''
| + | ===RAT OUTER MITOCHONDRIAL MEMBRANE CYTOCHROME B5=== |
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| - | ==Overview==
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| - | The reduction potential of cytochrome b5 is modulated via the formation of a complex with polylysine at the electrode surface (Rivera et al., Biochemistry, 1998, 37, 1485). This modulation is thought to originate from the neutralization of a solvent exposed heme propionate and from dehydration of the complex interface. Although direct evidence demonstrating that neutralization of the charge on the heme propionate contributes to the modulation of the redox potential of cytochrome b5 has been obtained, evidence demonstrating that water exclusion from the complex interface plays a similar role has not been conclusive. Herein we report the preparation of the V45I/V61I double mutant of rat liver outer mitochondrial membrane (OM) cytochrome b5. This mutant has been engineered with the aim of restricting water accessibility to the exposed heme edge of cytochrome b5. The X-ray crystal structure of the V45I/V61I mutant revealed that the side chain of Ile at positions 45 and 61 restricts water accessibility to the interior of the heme cavity and protects a large section of the heme edge from the aqueous environment. Electrochemical studies performed with the V45I/V61I mutant of cytochrome b5, and with a derivative in which the heme propionates have been converted into the corresponding dimethyl ester groups, clearly demonstrate that dehydration of the heme edge contributes to the modulation of the reduction potential of cytochrome b5. In fact, these studies showed that exclusion of water from the complex interface exerts an effect (approximately 40 mV shift) that is comparable, if not larger, than the one originating from neutralization of the charge on the solvent exposed heme propionate (approximately 30 mV shift). | + | The line below this paragraph, {{ABSTRACT_PUBMED_11197480}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 11197480 is the PubMed ID number. |
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| | + | {{ABSTRACT_PUBMED_11197480}} |
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| | ==About this Structure== | | ==About this Structure== |
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| | [[Category: Cytochrome]] | | [[Category: Cytochrome]] |
| | [[Category: Heme]] | | [[Category: Heme]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 15:31:41 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 1 02:00:15 2008'' |
Revision as of 23:00, 30 June 2008
Template:STRUCTURE 1eue
RAT OUTER MITOCHONDRIAL MEMBRANE CYTOCHROME B5
Template:ABSTRACT PUBMED 11197480
About this Structure
1EUE is a Single protein structure of sequence from Rattus norvegicus. Full crystallographic information is available from OCA.
Reference
Modulation of redox potential in electron transfer proteins: effects of complex formation on the active site microenvironment of cytochrome b5., Wirtz M, Oganesyan V, Zhang X, Studer J, Rivera M, Faraday Discuss. 2000;(116):221-34; discussion 257-68. PMID:11197480
Page seeded by OCA on Tue Jul 1 02:00:15 2008
